OBJECTIVES: To demonstrate the effects of different cytostatic drugs on carcinogen induced hepatomas in Rhesus monkeys by different imaging techniques. Experimental testing of a new contrast material in malignant tumors of the liver is one of the primary objectives of this study. METHODS EMPLOYED: Two imaging methods are employed in this investigation: A. Injection of an experimental contrast material containing emulsified oily contrast material (Ethiodol). Following the injection, computerized tomographic scans of the Rhesus liver are obtained with our EMI 5005 total body scanner. B. Selective hepatic angiography with conventional water soluble contrast media. Selective catheterization of the hepatic artery was performed by a cut-down of the external femoral artery. Flowing the injection of the contrast material directly into the hepatic artery, serial films of the liver are obtained.